Automatic telephone-exchange system.



F. N. REEVES & A. B. LUNDELL. AUTOMATIOTELEPHONB EXCHANGE SYSTEM.

. APPLICATION FILED MAY 10, 1913. 1,1 15,739.

\ Patented Nov. 3, 1914.

3 SHEETS-SHEET 1.

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APFLIOATION FILED MA Y 10, 1913,

Patented 3101231914,

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x I Q) W ff F. N. REEVES & A. E. LUNDELL. AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APPLICATION IILEDMAY 10, 1913,

Patented Nov. 3, 1914,

'3 SHEETS-SHEET 3.

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. A/ben E LurIde/K I Af/ V UNITED STATES PATENT oEEIcE.

EEANK N. EEEvEs, F NEWARK, NEw JERSEY, AND ALBEN E. LUNEEL on NEW YORK, N. Y., ASSIGNOBS T0 wEs'rEEN EL CTRIC COMPANY, OF NEW YORK, N. Y.,

A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE-EXCHANGE SYSTEM.

To all whom, it may concern Be it known that we, FRANK N; REEvEs and ALBEN E. LUNDELL, citizens of the United States, residin at Newark, in the county of Essex and tate of New Jersey, and at New York, in the county and State of New York, respectively, have invented a certain new and useful Improvement in an Automatic Telephone-Exchange System, of which the following is a full, clear, concise, and exact description.

This invention relates to an automatic switching system and particularly to a telephone exchange system comprising one or more main offices and one or more sub-offices or satellites associated and connected therewith by trunk lines. In a multi-ofiice satellite system there would be provided trunk lines leading from each main ofiice to each other main oflice, of the system, and other trunk lines leading from each main office to its own satellites. Such a system may have, for example, 10 main offices, each with its satellites having a capacity of 10,000,1ines, 'making a total capacity of100,000 lines.' 'The capacity of thesatellites mayrbefor instance, 1000 subscribers lines cachg-although obviously the number may varyaccording to the require-.-

ments met with in pi'actice. The subscrib ers lingsmay terminate either in a satellite or in a main exchange.

The object of this invention is to economize in the use of trunk lines between the satellites and the main exchange offices without the necessity of variable manipulation of the subscribers calling devices to discriminate between'calls local to the satellite and calls requiring connection through a main ofiice. To this end automatic discriminating means are providedwhich operate without the necessity of any knowledge on the part of the operator manipulatcalling device being manipulated in the same manner for all connections described, and strictly in accordance with the substation numbers of the subscribers wanted.

Specification of Letters Patent.

Application filed May 10, 1913. Serial No. 766,904.

switch mechanisms, each having access to a different group of lines, are simultaneously Patented N 0v; 3, 1914. I g

actuated by the first series of impulses from a controlling device and whereby, upon the succeeding series of impulses, the circuit is extended through only that one of said switches which has access to the line of. the called subscriber.

The invention will be more stood by reference to the accompanying drawings wherein Figure l is a diagrammatic illustration of readily the multi-oflice satellite system embodied in the invention, and Figs. 2 and 3 when placed together with Fig. 3- to the right of Fig. 2, represent the circuits and apparatus involved in establishing the connectionbetween subscribers at the same satellite. Fig. 2 represents a subscrlbers statlon and line switch and the repeater and register solector associated therewith. Fig. 3, repre: sents a hundreds selector-and a connector at the satellite and 21 called subscribers' line and substation apparatus. I i

- In Fig. l of the drawing, E represents a main oiiice connected by trunk lines 100 to other main ofiices A, B, C, D and F, it being understood that similar trunk lines would" extend from each main oflice to. each of the other main oflices of the exchange. Associated with the main ofiiceE, the confines of which are indicated by the dotted rectangle, are the satellites E E and the subscribers stations 6 e which are located atthesatllite E and other subscribers stations d (i connected directly witlrthe main ofiice. Similarly associated with the main ex- F F respectively, and subscribers""stations a a 6 6 etc., the satellites being represented by the circles and the subscribably extend from the second selector's l02" to third selectors at each of the other main exchanges, as well as to the third selector 103 at the same exchange therewith. In addition to the third selectors to whichth trunks from the second selectors extend,

other third selectors would be provided for the trunks extending from the second selectors of other exchanges.

The apparatus at a satellite office E for instance, may include trunk finders 105, re peaters 106, register selectors 107, hundreds selectors 108 and final connectors 109 and 110. The arrangement of the apparatus thus illustrated in Fig. 1 is such that the subscriber at station 6 for example, may complete a talking circuit to the subscribers station 6 over a local connecting circuit as 1.11 which is wholly within the satellite, or he may complete a connection to any other subscriber of the exchange system whose line does not terminate at the satellite E over a trunk line such as 112 leading to the main ofiice E from whence the connection may be extended in the usual manner according to the particular location of the wanted subscriber. If any subscriber other I than those connected to the satellite E de sires a connection with the subscriber at this satellite, the circuit would be completed by way of selectors'101, 102, 103 variously positioned at the main exchanges according to the location of' the calling subscriber, and through a trunk line as 113 to a final connector as 110 at the satellite E through which the subscribers thereat would be reached when the call originated at any point in the exchange other than at the satellite E of these connections are accomplished will be hereafter described in detail. At this point it is suflicient to say that when the subscriber at e removes his receiver from the hook, the trunk finder 105 will pick a pair of connecting circuts as 111 and 112 of which 111 leads to the connecting apparatus individual to the satellite, while 112 leads to a first selector 101 at the main exchange E. If now the subscriber at e sends calling impulses in correspondence to the number of some other station at the same satellite therewith, the brushes of the register selector 107' (the construction of which is similar to a final connector) will first he stepped up to the level corresponding to the number of tens thousand impulses in re-- sponse to the first series, and would then be rotated step-by-step in response to the thousand series' of impulses until the brushes thereof rest on the terminals representing the thousand at the satellite. Simultaneously with the actuation of the register selector, the brushes of a first selector 101 at the main exchange E will be stepped up to a corresponding level, and after having picked an idle second selector 102, the brushes of this second selector will be stepped up in unison with the rotary stepby-step movement of the brushes of the 5 register selector. If as assumed the brushes of the register selector now rest on contacts The manner in which certain representing the thousand of the satellite, a circuit for a cut-off relay will. be completed which will operate to interrupt the connecting circuit 112, and the selectors 101 and 102 will then obviously return to normal. The succeeding series of impulses will now act in the usual manner to cause the hundreds selector 108 to pick an idle final connector 109 having access to the desired subscribers line, and will then direct the brushes of this final connector to the terminals of this line.

Referring now to Figs. 2 and 3 wherein the circuits and apparatus required for the establishment of a connection between subscribers at e and 0 are illustrated. each subscribers line such as 200, 201, is provided at the substation with the usual telephone apparatus and with a calling device or interrupter 202, the purpose of which is to produce the operating impulses by inter rupting the circuit atthe substation, and at the satellite exchange with a trunk finder 1.05. The side 200 of the line leads to switch spring 203, also to the back contact 204 of armature 205 of the electromagnet 206. The side 201 of the line extends to the switch spring 207, also to the contact 208 of arma ture 209. In addition to these branches from the sides 200 and 201 of the line, additional branches are provided to multiple terminals 210 and 211 of the connectors through which the subscriber at e may be reached when called.

The trunk finders may comprise any suitable mechanism, that shown being similar to the switch shown in the British Patent No. 26,301 of 1906. The plunger 2120f this switch, as is well understood, always stands before the set of springs associated with an idle connecting circuit, and upon sufiicient energization of the electromagnet 206, thisplunger will be drawn forward, forcing the insulating ball 213 thereof between the in nermost springs of the set, whereby each of the four springs of the set is forced outwardly into engagement with its cooperating contact. The lead 214: associated through contact 215 with grounded switch spring 216 leads through the armature 250 and back contact to a master switch such as shown in the beforementioned British patent, whereby through the actuation of well known means, all of the remaining idle plungers of the group are moved to a position before the springs associated with the next idle trunk. Current is supplied to the lead 217 through the normally closed contact 218, but during the interval when the switch plungers are in transit from one position of rest to the next, this circuit is opened at contact 218 so that no finder mechanism can be actuated during this interval.

As hereinbefore stated, when a call is local to the satellite the calling subscribers line will be extended by the register selector 107, the hundreds selector 108 and the connector' 109 to the terminals of the called subscribers line. The apparatus of the reg .ister selector may be substantially that of a connector, the circuits, however, being yaried 1n order that 1t may fulfil its function in this invention. The hundreds selector andthe connector may comprise apparatus such as is well known in the art and need not be fully described here. A selector and connectorsimilar to that shown in the above 7 noted British patent, and more specifically are first stepped to a certain group of tens contacts and are then moved to the terminals of the called subscribers line. a

In Fig. 3 is shown the talking circuit conductor of the apparatus including contacts 400 and 101 of the hundreds selector .108, and 4:02 and 4:03 of the connector 109,

also condensers 4104 and 405, impedance coil relays 106, 107 connected in bridge of the talking circuit on each side of the condensers and through which talking current is supplied to the calling and called subscribers from battery 108. Associated with the selector and connector switches 108 and 109-there would preferably be local test and holding contacts 109 and 110 respectively. The brush of the latter is adapted to be connected to ground at 111 when the connector is brought to rest on the terminals of a called line, the object of this being to create a busy test condition at the multiple terminals of the called subscriber's line. It will, of course, be understood that .-the line of the called subscriber will have associated with it trunk finders such as shown in as- .sociation with the line of the calling subscriber e and that the connections to such apparatus will be made by the conductors 112 and 413.

As a further descript on of the apparatus employed is notbelieved to be necessary. the operation 'of the system will now be described Let-it be assumed that the subscriber at station e is calling the subscriber at 6 these two stations being connected to .-the same satellite. and let it be further assumed that this satellite contains a group of moves his receiver from the hook, thereby closing the line circuit through the winding 219 of the electromagnet 206, the current flowing from the live side of grounded battery 220 through 219, armature 209, contact 208, side 201 of the line, substation apparatus, side 200, contact 201, and armature 205 to ground. This partially energizesthe electroma-gnet 206 and the armature 221 alone is attracted. The attraction of this armature closes a circuit from grounded battery through the normallyclosed contact 218, lead 217, windings 222 and 223 of electromagnet 206, contact and armature221 to .ground. This results in the attraction of the'left armatures 209 and 205 and of the right armature 224. The armature 221 actuates the plunger 212 to force the insulating knob 213 between the innermost contact springs, thus closing all the springs now associated with this plunger to their contacts. The armature 221 in pulling up engaged the contact 225, closing a short circuit about the winding 222 whereby the electromagnet 206 is made slow to release. It may be noted that the energizing circuit through the Winding 223 will be interrupted at the contact 218 upon thegrounding of the contact 215 by the switch spring 216 as this places ground on the lead 214 to the master bank, thus causing the idle plungers to move .to a position before the next idle trunk.

However, as the electromagnet 206 is made slow to release by the short circuiting of the winding 222, all of its armatures will be held up until a holding circuit is completed through the .coil 226. i

3 When the plunger entered the set of springs, the sides of the subscribers line were extended by springs 203 and 207 and a circuit was completed as follows: from lire pole of grounded battery 251, left winding of relay 252 at the repeater, contact 253, armature 251, contact and spring 207, side 201 of the line, substation apparatus. side 2'00 of the line. switch sprin 203 and coir tact. conductor 227. winding of relay 275 ofthe register selector, contact 276, side switch wiper 2T7. conductor 278, armatu're 255 and back contact and right wi'nding of relay 25:3 to ground. This causes the energization of relays 275 and Armature 279 of relay closes the circuit for relay 280 from live pole of grounded battery 1206 from the live pole of grounded battery through 226, lead 228, contact and switch spring 229, conductor 230, armature 281 and contact to ground. As the electromagnet 206 is sluggish, this holding circuit will be established before said electromagnet will 284 as follows: from the live side of the grounded battery 285, side switch wiper 286, contact 287, winding of vertical magnet 283 and relay 284, front contact and armature 282, resistance 288 to ground The vertical magnet and the private magnet relay are prevented from operating by the resistance 288 in their circuit.

The relay 252 at the repeater attracted its armatures 256 and 257. The attraction of armature 257 closed a circuit for the slow acting relay 258 from the live pole of grounded battery through relay 258, front contactand armature 257 to ground. Relay 258 is thus energized and attracts its ai'anatur'es 259 and 260. The attraction of the armature 259 extended the circuit of the relay 261 through said armature 259 and front contact to the back contact of armature 257 of relay 252. The attraction of the armature 256 of relay 252 closed a shunt circuit about the condensers 263 and 264, including the impedance coil 265. The conductors 266 and 267 represent a trunk line as 112 (Fig. 1) leading to a first connector 101.

The apparatus and circuits are now in conditionfor the reception of the first series of selective impulses,'which in the case assumed will be 10. Upon each interruption of the circuit at the station E by the controller 202, the energizing circuit for the relays 275 and 252 will be interrupted and their armatures will fall back. We will first consider the effect of this series of inipulses on the register selector 107. The retraction of the armature 279 of relay 275 short circuits the resistance 288 and thus causes the energization of the vertical mag- As the release magnet relay 280 and the private magnet relay 284 are both made slow acting, they will not release during the brief intervals that they are deprived of current while the series of impulses is being transmitted.

In accordance with the assumption that the substation to be selected was No. 99,532. the first series of impulses would consist of ten interruptions of the circuit at the sta-. tion, causing the armature of relay 275 to be retracted ten times, resulting in ten energizations of the vertical magnet 288. thus raising the brushes of the register selector to the tenth level. The side switch having wipers 277, 286, 292 and 307 is actuated by the private magnet 290, which upon 8118177 gization of the relay 284 became energ1zed] by a circuit from battery through'the windingof said private magnet, contact and armature 291 of relay 284 to ground. Theq private magnet, however, does not aifect the movement of the side switch wipers upon energization, but is constructed to move all of the wipers of the side switch one step upon 'de'efnergization. The circuit 15 of the private magnet isinterrupted when the armature of .the private magnet relay 284 falls back due to the prolonged inclusion of the resistance 288 in its circuit upon f the termination of the first series of im- '30 pulses. The movement of the side switch wipers 292 and 277 will have no effect at this time. However, the movement of the side switch wiper 286 from contact 287 to its second position or contact 294 will re- 5 sult in the substitution of the rotary magnet 293 for the vertical magnet 283 in the will fall back, thus completing a circuit for the slow acting relay 261 from live pole of the grounded battery through 261, contact and armature 259 of relay 258, armature 257 and back contact of relay 252 to ground. Relays 258 and 261 being slow acting will hold up during the series of impulses.

The attraction of the armatures'266 and 267 of relay 261 interrupted the circuit from the sides 266 and 267 of the trunk through the condensers 263 and 264 respectively, and the armature 267 completed a short circuit about the impedance coil 265. Now upon each attraction of the armature 256 of the relay 252, a low resistance bridge will be completed across the trunk conductors 266.and 267, causing-the operation of the first selector 101 associated therewith in the usual and obvious manner, stepping the brushes thereof up in unison with the travel of the brushes at the register -selector 107. Upon the termination of this series of impulses, the first selector 101 would automatically hunt for an idle second selector 102 in the usual manner.

The apparatus is now in ,condition for the reception of the second series of impulses, which in the case assumed would. be 10. Upon the reception of this series of impulses, the brushes of theregister selector 107 will be moved to the tenth set of terminals in the tenth level, which, in the case assumed, is the set individual to the satellite E and at the termination of the series, the side switch will take another step, placing the wipers in third position. Simultaneously the brushes of the second selector 102,

(Fig l) will he stepped up to the tenth Qmayrbe -electricallyr-united; The tip and ected byr'a "loop con'ductdr 394. It ob- *iou's thatffsuch'va"tcondubtor may be pre- "dedi 'rfonveach' pair of'shh contacts or that be t-ied wgahetenaa loop 'conductor' protviidedqfbr eachlIei'rel-E""-The' sleeve contacts,

whowieverfiwith the-"exception of the tenth contact in; the 'tentlr'level, are all connected aito conductor 295': The-tip,- ring and sleeve contacts 302, 303 and'304 respect vely, of the "tenth leVel, how'evei-; are not-united to the other contacts in this" level, but instead are allQinfed to conductor-S296 and 297 and .298 -respectively,Hl'eading to a hundreds selector 1 08,? ;one hundreds selector being provided uforJeachpregister,selector. -In the call assmnedathe-brushes 299,:300 and 301 of the register, selector .willf-now be in engagement with, the contacts? $502; 303, 304 respectively, 30. and a. circuit will :be completedfor the cutmofi'frel; 270 asfollox'xstirbm the'livepole -o .f, =tlua'g undedgbatterythroughthe wind claw 27d .1; conductor 271, armature n eta-clay415;.conductor 298,-con 35.. tact 30.4.;b1iusl 301, conductor305, side switch .contact300;.waper307, armature 212 and back contact,conductorQ T3, contactand armature a 260 relay 25S to ground, I "Relay 270 is thereuponfenergized: and .a holding circuit is 40 1 completed ftherefor through its; armature I 'a ap rmmg 011mm, contact 1 215 1 and f prlng 2.1.6 to ground: This interrupts the circuit fo j the I relays 25 2}- and 275. The relay; 27,5 ,1 nioreovejr has uitstcircuit interrhpted whe n the side switc lrwiper 277 n1 s'to third position, Relays .252 and eref re .deenergized. Upon the jenergization{of relay 270 and the deener-z gi z a'tion of relav the: bridge across the sides 266,;"261 ef the-trunklinerof the sers 1 01Iai1d li02, ,is interrupted and these selectprs ,therefore returlnto normal.

Thei r'e 280 beingslow 'aeting'does not release as. ho lin" lcircuit is. completed over cqnduc tc'jr )1 ellithe hundreds se-' a lector108'. lithe brushes 299 and 300 tac'tg302fand 303,respec-,

s erswitch in third posico'n pleted, for the 1 relay 10' :ringfi'contacts nlay then be electrically cor 1 thencoliresponding contacts'of each level may 5 item. he live pole, I of h d l IQhrppfl Winding,

' h "t g test 0,8, ir 'r'."

t 255 andgfront 1 "hook, a complete talking circuit will be es 130 .tact and line finder switchspring 207 ,side

201 of the callingsubscribers l'ine,\substation' apparatus at e side 2000f the line,

- switch'spri'ng 203 and contact, conductor 227, side" switch wiper 292,'contact 309,

brush 300,"contact 303, conductor 2'97 and --lower winding of relay 416 to ground lay 416 pulls'up and-completes a circuit'for the-release magnet relay 4171mm live pole ofthe grounded battery through the'wi'iid- 'ing of said relay, front contact and armature of relay 416 t'o'ground.

Theattraction of the upper armature of relay417 placed ground upon the conductor 295, thus completing the circuit for the release magnet relay 280 of the register selector as follows: from live pole of the grounded bat-' tery through Winding of relay 280, conductor- 295, upper armature and contact of relay 417 to ground. The attraction of the lower armature of the relay 41? extended the circuit of the vertical magnet 418 and the private magnet relay 419 to the back contact of relay 416, this circuit being traced from battery through the side switch wiper 420 and contact, vertical magnet 418, relay 419, front contact and lower armature of 417 to back contact of relay 416.

The hundreds selector 108 is now incondition to receive the'next series of selective 9 5 impulses. As previously explained, only so much of the hundreds selector and fin'al' connector is shown in Fig. 3 as is necessary to illustrate the principal signaling and talking circuits to the called subscr'ibers station 6 711cm the brushes 299, 300 and 3010f the selector register engaged the contacts 302, 303 and 304 respectivelyQthe -relay 416 was energized as just explained and thus prepared the hundreds selector for operation in the well known manner by the impulses which subsequently occurred. In the case assumed-six impulses would now be sent'and1 the brushes of the hundreds selector would beraised to the sixth level when they would automatically hunt fol-an idle connector 109. The ensuing series of impulses would now cause the brushes'of theconnector first to be stepped up to the fQl llbh level sand then vupon the final series,

neotor'would stop on any-of the multiple terminals of the called subscribers line."

' Any well known method maybe employed for signaling the called subscriber, and upon his .response' bylifting his receiver from his tablished as follows from the transmitter at station 6 side 200 of the line, switch spring 203 and contact, conductor 227 side switch wiper 292, contact 309, brush 300,

contact 303, conductor 297, brush 401 and switch wipe1 277, conductor 278, armature 255 and front contact, front contact and armature 254, contact and switch spring 207, side 201 of the hue, back to the telephone apparatus at 6 v The talking current will be supplied to the calling subscribers station from battery 408 through the windings of the relay 406 and to the called subscribers station from battery 408 through" the windings of relay 407, the talking circuit being interrupted to battery between the connections of these relays to the sides of the line by condensers 404 and 405.

Upon the termination of the conversation when the calling subscriber replaces his receiver upon the hook, the circuit for the relays 4 16 and 406 will be interrupted and the hundreds selector 108 and the final connector 109 will then be returnedto normal in the usual manner. The deenergization of the relay 417 of the hundreds selector 108 will remove ground from the conductor 295, thus interrupting the circuit for the release magnet relay 280 of the register selector. Upon the retraction of the armature 282 of relay 280, the circuit for the release magnet 312 will be completed from the live pole of, grounded battery through winding of relay 312, off-normal contact 313, back contact and armature 282, back contact and armature 279 to ground, thus energizing the release magnet 312 and returning the register selector to normal. The retraction of the armature 281 of relay 280 will interrupt the circuit for the coil 226 of the electromagnet 206 and the trunk finder 105 will return to normal, thus interrupting at spring 216 the holding circuit for the cut-off relay 270 and allowing its armatures to be retracted. All the switching apparatus will now have assumed its normal position.

We will now assume a call which is not local to the satellite E and consequently one in which the called subscribers number is not in the ninety ninth thousand, and we will. further assume that the wanted subscribers number is 78,631. Again upon sending the first series of impulses, which in this case would now be eight, the brushes of the register select-or 107- at the satellite and of the first selector 101 at the main office E would he stepped up in unison as before described, and as before the hun dreds selector 101, upon the termination of this series of impulses, would select an idle selector 102 and the side switch wipers of the register selector 107 would move to second position, substituting the rotary ma et for the vertical magnet. Now upon sen ng the second series of impulses or in .the present case nine, the brushes of the second selector 102 at the main exchange E, and the brushes of the register selector .107 at the satellite would step in unison, the former being raised to the ninth level, while the latter would be directed to the ninth set of contacts in the eighth level. Upon the termination of the second series of impulses, the second selector 102 at the main exchange would automatically hunt for an idle third selector 103.

As previously described, all the corresponding contacts of the register selector 107 in a series of contacts or level, with the exception of the tenth set in the tenth level, are electrically united, the tip and ring contacts being connected by a conductor as 394,- while the sleeve contactsare joined to a conductor 295. The brushes 299, 300 and 301, will now rest, for example, in engagement with the contacts 314, 315 and 316 respectively. A circuit will now be completed for the private magnet relay 280 from the live pole of the groundedbattery through the winding of said relay, conductor 295, contact 316, brush 301, conductor 305, side switch contact 306, wiper 307 (the side switch being new in third position), armature 272 and back contact, contact and lower armature 260 of relay 258 to ground, thus holding the release magnet 280 energized and preventing the return to normal of the register selector. When the side switch wiper 277 moved to third position, the original energizing circuit for the relay 252 was interrupted but a substitute path was provided around, the interruption as follows: live pole of the grounded battery 251, left winding of relay 252, contact 253, armature 254, contact and brush 207 side 201 of the calling subscribers line, substation apparatus at 6 side 200 of the line, switch spring 203 and contact, conductor 227, side switch wiper 292, contact 309, brush 300, contact 315, loop conductor 394, contact 314, brush 299, contact 308, wiper 277, conductor 278, armature 255 and back contact and right winding of 252 to ground. The stepping relay 275 of the register selector having now been removed from connection to the calling subscribers line and the brushes being connected by the loop conductor 294, the succeeding series of impulses will have no further effect on the satellite apparatus with the exception of the repeater. If now the remaining series of impulses of 7, 4 and 2 respectively, be sent, the brushes of the ios third selector 103 will be stepped up to the seventh level in which they will automatifourth level, and then to rotate the brushes to the second set'of contacts in the fourth level or the terminalsof' the wanted subscribers line. As this operation would take place in a manner. which is obvious and is now well understood, further description thereof is believed to be unnecessary. Had the first series consisted often impulses and the second series any number but ten, obviously precisely the same result would have been obtained as all the terminals in the tenth level, with the exception of the final or tenth set, are joinedtogether in the same manner as are the contacts of the other levels. i i

W'hile injthe embodiment of the system herein specifically described the invention is disclosed as'applied to a satellite exchange system, it is,obvious that the system is adapted, with slight modification, to a broader application as, for illustration, dis

criminatingbetween groups of subscribers lines at the same ofiice. It should, therefore, be understood that the invention is to 'be limited merely by the scope of the appended devices associated with the satellite forgoyerning the movement of said switching mechanism, means whereby 'the first series of selective impulses will effect the simultaneous actuation of switching mechanism at said main exchange and at said satellite, and means operated under the control of a controlling device when manipulated in accordance with the number of the wanted subscriber atsaid satellite for returning said main ofiice switching mechanism to normal and for efiecting a talking connection through the "switching mechanism at said satellite.

' 2. In a telephone system, a ma n'oflice, a

satellite ofiice, a seriesof automatic switching mechanismsat said main oilice and at said satellite respectively, whereby the line of a calling subscribermay be extended to other subscribers at the exchange or at said satellite, controlling devices associated with said satellite for governing the operation of said switching 'n'iechanisms and means whereby the first series of impulses transmitted from one of said controlling devices will simultaneously effect the operation of switching mechanism at the main exchange and at the satellite, and means operating when the wanted subscriber is at the satellite for interrupting the controlling circuitto the switching mechanism at the main exchange and for extending the line oft-he calling subscriber through satellite switching mechanism to the line of the subscriber called.

3. In a telephone exchange system, a main office, a satellite oflice, interoffice trunk lines between said satellite and said main 'oflice, local trunk lines at said satellite, means operated uponthe initiation of a call at the satellite for associating the calling subscribers line with an interofiice and a local trunk, automatic switching mechanism at said main oflice and at said satellite respectively, for efiecting connection between subscribers, controlling devices associated with said satellite for governing the movement of said switches, and means operated under the control of a controlling device when manipulated in accordance with the number of a wanted subscriber at the satellite whereby the first series of impulses Will eflect the including a register selector at said satellite,

controlling devices for governing the movement of sald switches, and means operated under the control of a controlling device at the satellite when manipulated in accord ance with the number of a wanted subscriber at said satellite, whereby said register selector and switching'mechanism at said main exchange will be simultaneously actuated by the first series of impulses, and whereby the successive series of impulses will cause the register selector to alter an electrical circuit, and a relay in said circuit for efiecting the release of said main office mechanism.

5. In a telephone exchange system a main ofiice, a satellite oflice, interoflice trunk lines between said satellite and said main oflice, local trunk lines at said satellite, automatic switching mechanism at said exchange and at said satellite respectively for effecting connection between subscribers, controlling devices at said satellite substations for governing the movement of said switches, a cutoff relay, and means operated under the control of a controlling device when manipulated in accordance with the number 'of a mechanism and wanted subscriber at the satellite, whereby switchin 'mechanism at said main exchange and at the satellite will be simultaneously actuated by the first series of impulses and the successive series will effect the energization of said cut-ofi' relay to interrupt the connection to the main office switching extend the connection through the satellite switching mechanism to the wanted subscriber.

6. In a telephone exchange system, a main oflice, a satellite ofiice, interofiice trunks from said satellite to said main ofiice, local trunks at said satellite, automatic switching mechanism for effecting connection between subscribers, said switching mechanism including a register selector at said satellite, controlling devices associated with sa d satellite for governing the movement of said switches, means at said satellite for associating the line of a calling subscriber thereat with an interofiice trunk and a local trunk upon initiating a call whereby switching mechanism at the main office and at the satellite will be simultaneously actuated by the first series of impulses, a cut-off relay, said register selector being operated under the control of a controlling device when manipulated in accordance with the number of a wanted subscriber at the satellite to complete a circuit for said cut-ofi relay, whereby the interoflice trunk line will be interrupted and the connection will be completed through local switching mechanism. 7 -In a telephone exchange system, a main office, a satellite ofiice, interofiice trunk lines from said satellite to said main ofiice, local trunks at said satellite, automatic switching mechanism at said main exchange and at said satellite for effecting connection between subscribers, controlling devices at said satellite substations for governing the movement of said switches, cut-off relays for interrupting said interoflice trunks, and means operated under the control of a controlling device when manipulated in accordance with the number of a wanted subscriber at the satellite, whereby the simulta neous actuation of switching mechanism at said main exchange and at said satellite will be eii'ected by the first series of impulses, and whereby the successive series will cause the energization of one of said cut-ofi" relays and complete the connection through the satellite switching mechanism only when the wanted subscriber is at the satellite.

8. In a telephone system, subscribers lines, automatic switches for interconnecting said lines, one group of said switches being provided to extend a connection to lines of a certain group only, and other switches arranged to extend a calling line to other subscribers lines, controlling devices for governing the operation of said switches, and means whereby the first series of impulses transmitted from one of said controlling devices will simultaneously actuate a switch in said group and one of said other switches, and means operating when the calling and called lines are in the same group for completing the connection through that switch individual to said group and for interrupting the controlling circuit to the other switching mechanism.

9. In a telephone system, groups of subscribers lines, automatic switches for inter connecting said .lines, one group of said switches being provided to extend the con nection to lines of a certain group and another group of said switches arranged to extend a calling line to other subscribers lines, controlling devices for governing the operation of said switches, and means operating under the control of a controlling device when manipulated in accordance with the number of a wanted subscriber, whereby the first series of controlling impulses will simultaneously actuate a switch in each of said groups, and whereby the succeeding series of impulses will extend the connection through only that one of said simultaneously operated switches which has access to the group of the called subscriber.

10. In a telephone exchange a group 01 subscribers lines, other subscribers lines, automatic switches for interconnecting said lines, a group of switches for extending a connection to lines of said group only and other switches arranged to extend a connection to other subscribers lines, controlling devices for governing the operation of said switches, and means operating under the control of a controlling device when manipulated in accordance with the number of a wanted subscriber, whereby the first series of controlling impulses transmitted will simultaneously actuate a switch in said group and one of said other switches, and whereby the succeeding series of impulses will extend the connection through one or the other of said simultaneously actuated switches according to whether the called subscriber is located in the same group with the calling subscriber or is external thereto.

11. In a telephone system, subscribers lines, a plurality of groups of switches for interconnecting said lines, said groups being arranged to extend a connection to diflerent groups of subscribers, controlling devices for governing the operation of said switches, and means actuated upon the operation of one of said controlling devices for first simultaneously actuating a switch in each group and for subsequently releasing all but that one of said switches which has access to the line of the called subscriber.

12. In a telephone system, subscribers lines, a plurality of groups of switches for interconnecting said lines, the switches of said groups being arranged to extend a conoperation of said switches, and means actuthe wanted subscriber and for releasing the 10 other switches. j

In witness whereof, we hereunto subscribe our names this 7th day of May A. 1)., 1913.

- v. FRANK N. REEVES. o 4 ALBEN E. LUNDELL.

Witnesses:

W. F. HoFFMAN,

H. BR WN.

nection to different grou s of'subs cribers lines controlling devices or governing the ated when one of said controlling devices is operated. in accordance with the number of a. wanted subscriber for first simultaneously actuating a switch in each group .and for subsequently extendin the connection through one of said swltches to the line of l I t iopiel of this patent may be obtained for five cents each, by addressing the Commissioner oi'latents,

' Washington, D. 0, 

